1. Field of the invention
This invention relates generally to a heat-insulated housing used in refrigerators or the like, and more particularly to a structure for mounting corner covers on corners of an opening of such a heat-insulated housing.
2. Description of the prior art
A heat-insulated housing conventionally used in refrigerators or the like generally has an opening defined by an inwardly bent portion formed in an open edge of an outer box and an outwardly bent portion formed in an open edge of an inner box. The inner box is disposed inside the outer box so that the bent portions are opposed to each other. Decorative frames are then attached to the boxes so as to cover surfaces of the bent portions. A space between the outer and inner boxes is filled with a heat-insulating material such as a foaming resin. In order to prevent the space from varying due to a filling pressure, generally L-shaped reinforcing metal fixtures are fixed over both bent portions at comers of the opening respectively. When fixed to each opening corner, however, the reinforcing fixture blocks the decorative frames adjacent thereto such that ends of the frames cannot extend up to the comers. This results in a bad appearance. In view of the problem, generally L-shaped comer covers are mounted on the comers so as to cover the reinforcing fixtures respectively.
Japanese patent publication No. 8-152255A discloses a structure for mounting the corner covers of the type described above. In the disclosed mounting structure, a pair of elastic engagement protrusions are formed on the backside of one of two plate-shaped portions of a generally L-shaped corner cover. The paired protrusions have claws on distal ends respectively. Each reinforcing fixture has engagement through holes. The elastic protrusions are inserted into the respective holes so that the claws elastically engage edges of the holes respectively. As a result, the corner cover is prevented from falling off when mounted on the corner.
However, the elastic protrusions cannot always be inserted into the engagement holes of the reinforcing fixture by a constant depth. For example, when the covers are mounted after the space between the outer and inner boxes has been filled with the heat-insulating material, the depths of the inserted elastic protrusions sometimes differ depending upon the hardness of the heat-insulating material. Further, small screws are usually used to fix the reinforcing fixtures to the bent portions of the inner and outer boxes. Further, a moltprene tape is sometimes wound on the reinforcing fixtures to prevent leakage of the foaming resin. A fastening force of each screw and a winding force of the moltprene tape raise or lower the positions of the reinforcing fixtures relative to the bent portions. This also results in differences in the depths of the elastic protrusions inserted into the respective holes.
The conventional elastic protrusion is provided with only a single claw on the distal end thereof Accordingly, in a case where the depths of the elastic protrusions inserted into the holes are not constant, as described above, the claw cannot engage the open edge of the hole when the elastic protrusion is inserted in a excessively shallow engagement hole. On the other hand, when the elastic protrusion is inserted in an excessively deep engagement hole, a gap is defined between the claw and the open edge of the hole. In both cases, the claw cannot desirably engage the open edge of the hole. Thus, the corner cover cannot reliably be mounted on the corner in the prior art.
Therefore, an object of the present invention is to provide a heat-insulated housing in which the corner cover is reliably engageable with the opening edge of the engagement hole to be mounted at each corner of the opening.
The present invention provides a heat-insulated housing comprising a housing body having a rectangular opening in one side thereof. The opening has four corners each of which is defined by two side plates generally perpendicular to each other. Either one of the side plates is formed with a hole having an engagement open edge. A corner cover includes two closing plates disposed to be generally perpendicular to each other so as to have a generally L-shaped section. The closing plates have backs thereof abutting against the side plates of the housing body respectively. An engagement protrusion is formed on the back of either closing plate abutting against the side plate formed with the hole. The protrusion is inserted into the hole of the side plate and elastically deformable. A plurality of engagement teeth are formed on the protrusion so as to be aligned in a direction of insertion of the protrusion. One of the teeth elastically engages the opening edge of the hole when the protrusion is inserted into the hole.
According to the above-described heat-insulating housing, the protrusion has a plurality of the engaging teeth formed thereon so as to be aligned properly. Accordingly, even when the protrusion is inserted into a hole having a different depth, any on of the teeth engages the opening edge of the hole. Consequently, the corner cover can reliably be mounted on the corner.
The protrusion preferably has a pointed distal end. For example, when the space between the outer and inner boxes is filled with a heat-insulating material before the mounting of the corner covers, the protrusion can smoothly be inserted into the hole, biting into the heat-insulating material.
The protrusion preferably includes an insertion body protruding from the closing plate and a flexible piece formed by folding a distal end of the insertion body, the teeth being formed on the flexible piece. For example, when supplied into the space after the corner covers have been mounted on the corners, the heat-insulating material enters a space between a root of the flexible piece and the insertion body. Consequently, the heat-insulating material serves to increase an engaging force of the corner cover.
The flexible piece preferably has a face on which the teeth are formed, the face being curved so that an amount of flexure of the flexible piece becomes approximately constant when each tooth engages the opening edge of the hole. The amount of flexure of the flexible piece is maintained approximately at a constant value over its length when the teeth sequentially engage the opening edge of the hole. Consequently, the corner cover can readily be mounted on the corner.
The flexible piece preferably includes a flexure limiting portion abutting against the insertion body of the protrusion to limit an amount of flexure developed in a direction in which the flexible piece comes close to the insertion body of the protrusion. The protrusion is inserted into the hole so that any one of the teeth engages the opening edge of the hole. The engagement of the teeth with the edge of the hole limits the flexure of the flexible piece toward the insertion body side. Consequently, the engaging force can be increased and the corner cover can be prevented from having lateral slippage in the hole.
A pair of the engagement protrusions are preferably provided on the backside of the closing plate of the corner cover so as to be spaced from each other with the teeth of the respective protrusions being directed outward, and the insertion bodies of the protrusions are connected by a connecting portion. Since a pair of the protrusions are provided, the corner cover can stably be engaged in a well-balanced state. Further, since the protrusions are connected to each other so as to be prevented from straddling outward, the protrusions can smoothly be inserted into the hole.